Hi, We found this kernel NULL pointer issue with latest linux-block/for-next, please check it. Kernel repo: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git [ 112.483804] BUG: kernel NULL pointer dereference, address: 0000000000000048 [ 112.490809] #PF: supervisor read access in kernel mode [ 112.495976] #PF: error_code(0x0000) - not-present page [ 112.501141] PGD 800000044d20c067 P4D 800000044d20c067 PUD 4734d5067 PMD 0 [ 112.508057] Oops: 0000 [#1] PREEMPT SMP PTI [ 112.512265] CPU: 24 PID: 7767 Comm: user-data Kdump: loaded Not tainted 6.4.0-rc1+ #1 [ 112.520141] Hardware name: HPE ProLiant DL380 Gen10/ProLiant DL380 Gen10, BIOS U30 06/20/2018 [ 112.528713] RIP: 0010:bfq_bio_bfqg+0x8/0x80 [ 112.532925] Code: 6b 70 48 89 43 60 5b 5d c3 cc cc cc cc 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 41 54 53 <48> 8b 46 48 48 89 fb 48 89 f7 48 85 c0 74 26 48 63 15 72 40 6b 01 [ 112.551805] RSP: 0018:ffffaed687ef3b30 EFLAGS: 00010096 [ 112.557058] RAX: ffff9a90f2600000 RBX: ffff9a90f2600000 RCX: 0000000000000001 [ 112.564232] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff9a90f2600000 [ 112.571408] RBP: ffff9a90c508d500 R08: ffff9a90e2b8a688 R09: ffff9a90e2b8a688 [ 112.578581] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 112.585756] R13: ffff9a90c508d500 R14: 0000000000000000 R15: 0000000000000000 [ 112.592930] FS: 00007fe41b0f0880(0000) GS:ffff9a94afc00000(0000) knlGS:0000000000000000 [ 112.601065] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 112.606842] CR2: 0000000000000048 CR3: 000000046346e005 CR4: 00000000007706e0 [ 112.614016] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 112.621189] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 112.628362] PKRU: 55555554 [ 112.631082] Call Trace: [ 112.633539] <TASK> [ 112.635650] bfq_bic_update_cgroup+0x2c/0x240 [ 112.640033] bfq_init_rq+0xdd/0x670 [ 112.643545] ? blk_rq_map_user_iov+0xc5/0x2f0 [ 112.647931] bfq_insert_request.isra.0+0x5d/0x250 [ 112.652663] bfq_insert_requests+0x59/0x80 [ 112.656782] blk_mq_flush_plug_list+0x172/0x570 [ 112.661342] blk_add_rq_to_plug+0x45/0x150 [ 112.665462] nvme_uring_cmd_io+0x242/0x390 [nvme_core] [ 112.670652] io_uring_cmd+0x95/0x120 [ 112.674250] io_issue_sqe+0x199/0x3d0 [ 112.677932] io_submit_sqes+0x119/0x3d0 [ 112.681788] __do_sys_io_uring_enter+0x2c2/0x470 [ 112.686433] do_syscall_64+0x59/0x90 [ 112.690031] ? exc_page_fault+0x65/0x150 [ 112.693977] entry_SYSCALL_64_after_hwframe+0x72/0xdc [ 112.699057] RIP: 0033:0x7fe41ae3ee5d [ 112.702651] Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 93 af 1b 00 f7 d8 64 89 01 48 [ 112.721530] RSP: 002b:00007ffc6fdebc28 EFLAGS: 00000206 ORIG_RAX: 00000000000001aa [ 112.729143] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fe41ae3ee5d [ 112.736317] RDX: 0000000000000001 RSI: 0000000000000080 RDI: 0000000000000005 [ 112.743492] RBP: 00007ffc6fdec730 R08: 0000000000000000 R09: 0000000000000080 [ 112.750666] R10: 0000000000000001 R11: 0000000000000206 R12: 00007ffc6fdec848 [ 112.757841] R13: 0000000000401346 R14: 0000000000403de8 R15: 00007fe41b32c000 [ 112.765019] </TASK>
